The present invention relates to a molded cross vehicle beam, which includes a hollow blow molded thermoplastic rigid member that is integrally attached to a rigid support, e.g., a U-shaped metal plate, and at least one attachment element. The attachment element serves as a means of attaching the molded cross vehicle beam to a separate structure, such as the door-pillars of an automobile. A thermoplastic parison precursor of the hollow rigid thermoplastic member is blow molded against the rigid support and the attachment element. Portions of the thermoplastic parison extend through perforations in each of the rigid support and the attachment element, thereby attaching the hollow thermoplastic rigid member to the rigid support and the attachment element. The present invention also relates to a process by which the molded cross vehicle beam is prepared.
The majority of transportation vehicles, such as automobiles, trucks and buses, include a cross vehicle beam, which typically spans laterally across the forward portion of the passenger or operator compartment. In the case of an automobile, the cross vehicle beam (commonly referred to as a cross car beam) is typically located behind the dashboard, and is attached to the door-pillars (A-pillars) of the automobile. The cross vehicle beam, which is typically fabricated from metal, provides rigidity and structural support to the vehicle, e.g., relative to a lateral impact upon the vehicle.
The heating, ventilating and air conditioning (HVAC) system of a vehicle, such as an automobile, is typically located behind the dashboard. Air is transported through the HVAC system generally by means of a plastic conduit. Often, the plastic conduit of the HVAC system is attached to and supported by the cross vehicle beam.
Typically the plastic conduit and the cross vehicle beam are separately fabricated, and then attached together in a separate step. The plastic conduit and cross vehicle beam e.g., in the form of a metal beam or tube, are typically attached together by means of, for example, fasteners, adhesives, straps and/or brackets. Such attachment methods typically involve a series of manufacturing steps, and the use of additional materials, e.g., rivets, bolts and adhesives. In the case of an automotive application, for example, the separately fabricated cross car beam and plastic conduit, when assembled together, can take up an undesirably large amount of space within the passenger compartment.
In the transportation industries, e.g., the automotive and aircraft industries, it is desirable to minimize the weight of the vehicle or aircraft in an effort towards maximizing fuel efficiency. The total weight of a vehicle or aircraft can be reduced by reducing the weight of its components. However, it is generally required that the strength and rigidity of a component not be compromised as the weight of the component is reduced. It is also desirable in the transportation industries to minimize the space occupied by various components that are incorporated into the vehicle or aircraft.
A need thus exists for the development of cross vehicle beams that include a rigid support and a rigid thermoplastic hollow member attached thereto, that provide a combination of structural stability, reduced weight and compact (or space saving) design. In addition it is desirable that such newly developed cross vehicle beams also include a means for attaching the beam to a separate structure, such as the door-pillars of an automobile. A need also exists with regard to the development of new methods of preparing such molded articles in which the rigid thermoplastic hollow member is concurrently molded and fixedly attached to a rigid support and an attachment element during formation of the cross vehicle beam.
U.S. Pat. No. 5,354,114 discloses an integrated cross car structural duct cluster. The integrated cross car structural duct cluster of the ""114 patent is disclosed as including a steel plate that is attached to a molded plastic body of a thermoplastic or thermoset material.
In accordance with the present invention, there is provided a molded cross vehicle beam comprising:
(a) a rigid support having a first surface, a second surface and a plurality of perforations having edges;
(b) at least one attachment element having a first surface, a second surface and a plurality of perforations having edges, said attachment element providing means of attaching said molded cross vehicle beam to a separate structure; and
(c) a rigid molded member of thermoplastic material, at least a portion of said rigid molded member being in abutting relationship with the first surface of said rigid support (a) and the first surface of said attachment element (b), said rigid molded member having a hollow interior,
wherein said molded cross vehicle beam is prepared by a process comprising blow molding a thermoplastic parison precursor of said rigid molded member (c) onto the first surface of said rigid support (a) and the first surface of said attachment element (b), a portion of the thermoplastic material of said thermoplastic parison extends through at least some of said perforations of said rigid support (a) and said attachment element (b), the edges of said perforations being embedded in the plastic material extending therethrough, thereby fixedly attaching said rigid molded member (c) to said rigid support (a) and said attachment element (b).
In further accordance with the present invention, there is also provided a method of preparing a molded cross vehicle beam comprising a rigid molded hollow thermoplastic member fixedly attached to a rigid support and at least one attachment element, said method comprising:
(I) placing said rigid support and said attachment element in a mold,
said rigid support having a plurality of perforations having edges, a first surface and a second surface, and
said attachment element having a plurality of perforations having edges, a first surface and a second surface; and
(II) blow molding a thermoplastic parison precursor of said rigid hollow member against the first surface of said rigid support and the first surface of said attachment element;
wherein a portion of the thermoplastic material of said thermoplastic parison extends through at least some of said perforations of said rigid support and said attachment element, the edges of said perforations being embedded in the plastic material extending therethrough, thereby attaching fixedly said rigid hollow member to said rigid support and to said attachment element.
The features that characterize the present invention are pointed out with particularity in the claims, which are annexed to and form a part of this disclosure. These and other features of the invention, its operating advantages and the specific objects obtained by its use will be more fully understood from the following detailed description and accompanying drawings in which preferred embodiments of the invention are illustrated and described.
Unless otherwise indicated, all numbers or expressions, such as those expressing structural dimensions, quantities of ingredients, etc. used in the specification and claims are understood as modified in all instances by the term xe2x80x9caboutxe2x80x9d.